Dicarboxylic compounds having 2,4-quinazol inedione rings

ABSTRACT

A dicarboxylic compound complying with one of the general formulae:   IN WHICH R is a divalent radical selected from the aliphatic, alicyclic and aromatic radicals the aliphatic containing 1-20 carbon atoms and the other containing from 5 to 20 carbon atoms, R1 is selected from the hydrogen atom and the alkyl and cycloalkyl groups containing from 1 to 10 carbon atoms and R2 is selected from the alkyl and cycloalkyl groups containing from 1 to 10 carbon atoms, the polyester resins derived therefrom being usable as enamelling composition, particularly for coating metal wires.

United States Patent [19] Cohen et al.

[ 1 May 6,1975

[ DICARBOXYLIC COMPOUNDS HAVING 2,4-QUINAZOL INEDIONE RINGS [75] Inventors: Choua Cohen, Grenoble; Bruno Durif-Varambon, Eybens; Robert Salle; Bernard Sillion, both of Grenoble, all of France [73] Assignee: Institut Francais du Petrole, des

Carburants et Luhritiants, Rueil-Malmaison, France [22] Filed: Sept. 13, 1972 [21] Appl. No.: 288,478

[30] Foreign Application Priority Data Sept. 15, 1971 France 71.33327 Apr. 10, 1972 France 72.12565 [52] U.S. Cl. 260/256.4 Q; 260/75 N; 260/260; 260/453 Ar; 260/453 AM;- 260/453 AL;

[51] Int. Cl ..C07d 51/48 [58] Field of Search 260/256.4 Q, 260

[56] References Cited UNITED STATES PATENTS 3,781,288 12/1973 Rosenfeld et a1 260/260 FOREIGN PATENTS OR APPLICATIONS 1,478,938 3/1967 France Primary ExaminerI-Ienry R. Jiles Assistant Examiner-S. D. Winters Attorney, Agent, or FirmMillen, Raptes & White [57] ABSTRACT A dicarboxylic compound complying with one of the general formulae:

- and nos l 2 n P. co s 11 Claims, No Drawings DICARBOXYLIC COMPOUNDS HAVING 2,4-QUINAZOL INEDIONE RINGS This invention relates to dicarboxylic compounds having 2,4-quinazolinedione rings and their process of manufacture.

It also relates to the use of these dicarboxylic compounds having 2,4-quinazolinedione rings in the manufacture of new resins and particularly of polyester resins.

It also concerns new polyester resins having 2,4- quinazolinedione rings. It has also for object the use of these new polyester resins in the manufacture of coating materials and particularly varnishes for enamelling metallic electric conductors.

For the manufacture of enamelling varnishes, particularly for the metallic electric conductors, it has already been proposed, according to the French Pat. Nos. 1,368,741; 1,478,938; 1,511,96l, and in the French patent application 2,009,052, to make use of polyester-imide resins which consist generally either of condensation products prepared from reactants already containing cyclic imide groups, or of condensation products in which the formation of imide cycles occurs during the condensation of the reactants.

The invention has for object to provide new polymeric substances free of imide cycles, which make it possible to prepare, at low cost, coating compositions exhibiting a remarkable thermal stability and high softness and adhesive properties, these properties being such that they can be used advantageously for manufacturing insulating varnishes suitable for enamelling metal electric conductors.

The invention has also for object to provide insulating varnishes for metal electric conductors which exhibit the required electrical, thermal, mechanical and chemical properties and particularly a resistance to heat which make possible their use over a long period at high temperatures, particularly a continuous operation at a temperature of 180C or more (H class of insulating materials).

It has as a further object to provide new compounds which may be prepared at low cost and which can be used advantageously as starting materials in the manufacture of the above-mentioned polymeric substances.

The invention has, as more particular object, to proin which R is a divalent radical selected from the aliphatic, alicyclic and aromatic radicals, the aliphatic containing l-2O carbon atoms and the other containing from 5 to 20 carbon atoms; R is selected from the hydrogen atom and alkyl and cycloalkyl groups containing from I to 10 carbon atoms, and R is selected from alkyl and cycloalkyl groups containing from 1 to 10 carbon atoms.

These dicarboxylic compounds may be prepared from aminodicarboxylic acids or from mono or diesters of such acids, complying with the general formula:

OCN-R-NCO in which R is defined as above, or with an alkyl or aryl diurethane of such a diisocyanate (so-called hidden" diisocyanate).

There is generally used a molar ratio of the aminodicarboxylic compound (111) to the diisocyanate (IV) of at least 2. There is obtained an intermediary bis-urea (V) which may be converted immediately or in a further stage into his (2,4-quinazolinedione) by cyclisation accompanied with the removal of water or alcohol.

The reaction conforms with the following scheme:

R t-/ OCN R- NCO 1 002R 3 5 a R 0 y (III) (III) (IV) 0 R R 0 0 a I The mono and diesters complying with the general formula (ll) may be prepared by reacting a compound of formula (Ill) with an isocyanate of general formula:

in which R and R have the same meaning as above, or with an alkyl or aryl urethane of such an isocyanate (so-called hidden isocyanate).

The manufacturing procedure which comprises adding the isocyanate to an amine group of the aminodicarboxylic compound with the formation of intermediary urea (Vll) followed with the cyclisation of the urea to 2,4-quinazolinedione, is as follows:

As examples of diisocyanates conforming with the formula (IV) above, there can be mentioned:

Polymethylene-diisocyanates of general formula in which n for example is a number from 4 to 8, the phenylene-diisocyanates (optionally substituted with alkyl groups or halogen atoms) such as for example the mand p-phenylene diisocyanates, the 2,4 and 2,6 tolylene-diisocyanates, the ethylbenzene-diisocyanates or the chloro p-phenylene-diisocyanate; the 4,4'diisocyanato-diphenylmethane; the 4,4'-diisocyanatodiphenylether, the 4,4'-diisocyanato-biphenyle or the diisocyanato-naphthalenes.

The isocyanates of the general formula (VI), the use of which is preferred according to this invention, are the aliphatic or aromatic isocyanates, which further contain an alkyl or cycloalkyl ester function.

2 1 A ocn-a-cc R s R o c 2 2 3 co n' (V) NN O jpfl 00 11 1* 2 K 01i 0 As examples there can be mentioned: the esters of isocyanate-acetic acid (R contains 1 carbon atom), the esters of a or B -isocyanato-propionic acid (R contains two carbon atoms), the esters of isocyanato-butyric acid (R contains three carbon atoms), the esters of isocyanatoundecanoic acid, the esters of 3- or 4- isocyanato-benzoic acid, or the esters of the isocyanato-naphthoic acid.

As examples of amino-dicarboxylic compounds, complying with general formula (Ill), there can be mentioned:

The Z-amino terephthalic, 2-amino-5 -bromo terephthalic, 3-amino phthalic, 2-amino isophthalic, Z-amino S-methyl isophthalic acids and the alkyl and cycloalkyl (VII) esters of said acids.

The reaction between the isocyanate compound of formula (IV) or (VI) and the amino-dicarboxylic compound of formula (Ill) may be conducted according to various methods,

When the amino-dicarboxylic compound (Ill) is a dicarboxylic acid or a mono-ester, i.e. when at least one of the radicals R and R is the hydrogen atoms, it is possible to proceed to an interfacial reaction, for example, by dissolving said amino-dicarboxylic compound in an alkaline aqueous solution and adding to the solution, under stirring, the isocyanate compound dissolved in an organic solvent immiscible with water. The reaction may also be conducted in solution in a solvent inert with respect to the isocyanates such, for example, as the hydrocarbon solvents, pyridine, dioxane, dimethylacetamide, dimcthylformamide, or N- 'methylpyrrolidone, provided that the solvents of the amide type be used only when the reaction temperature is very substantially lower than their reaction temperature with the isocyanates.

The reactions in solution are preferably conducted at temperatures lower than 100C in order to prevent secondary reactions of addition of one or more isocyanate groups onto a free carboxylic group.

It is possible, if so desired, to increase the reaction velocity by adding an usual catalyst such, for example, as a metal alcoholate or a tertiary amine.

When the reaction is conducted at low temperature (for example lower than 60C), there is essentially obtained an intermediate urea complying with formula (V) or (VII). The stage for obtaining the final compound (l) or (II), i.e. the cyclisation reaction of the urea to the 2,4-quinazolinedione heterocycle, may be achieved in various manners, for example, in a thermal or chemical way. The thermal treatment may be carried out either in the absence of solvent, or in a high boiling solvent, optionally in the presence of a catalyst (preferably pyridine), generally at a temperature from l to 300C. The chemical cyclisation consists of treating the intermediary urea (V) or (Vll) by a dehydrating agent such, for example, as sulfuric acid, polyphosphoric acid or an anhydride of a carboxylic acid such as acetic anhydride, in the presence or the absence of a catalyst.

When a diester in used as amino-dicarboxylic cornpound (Ill), i.e. and R and R are each an alkyl or cycloalkyl group, the reaction may be conducted with the isocyanate compound by heating in the presence or the absence of a solvent. The reaction temperature is generally from 50 to 220C, and preferably at least l00C. It is obvious that the use of a hidden isocyanate requires a sufficiently high reaction temperature in order that the isocyanate itself be released.

The reaction time depends on the operating conditions and of the reactants, but in most cases, it is from 5 to 48 hours.

The solvents to be used in this reaction must be inert with respect to the reactants, or must react with them in a reversible manner, this being, for example, the case of the alcohols or phenols with respect to the isocyanates; other examples of solvents which can be used are: hydrocarbons, aliphatic or alicyclic ethers, pyridine, dimethylformamide, dimethylacetamide or N-methyl-pyrrolidone, provided that the solvents of the amide type are always used when the reaction temperature is substantially lower than their reaction temperature with the isocyanates.

It is possible, if so desired, to increase the velocity of the reaction of addition onto the isocyanates by making use of a conventional catalyst, such for example, as a tertiary amine.

HOOC

NH\ N- R- soon Generally the reaction is carried out, with substantially stoichiometrical amounts of the reactants, but the reaction may also be conducted in the presence of a slight excess of the amino-carboxylic compound.

When the reaction is conducted at a sufficiently high temperature (generally higher than l0OC), there are obtained quinazolinediones.diesters (l) or (ll) directly, the cyclisation reaction of the intermediate urea being effected during the heating step.

The structure of the products obtained according to the above-mentioned methods may be determined by elementary analysis or from the infrared absorption spectrum, which shows, in particular, characteristic absorption bands in the vicinity of 1720 and i670 cm (as mentioned for example by A. R. KATRIZKY in.

Physical Methods in Heterocyclic chemistry, Academic press, (1963), vol. ll, page 270).

The dicarboxylic compounds having 2,4- quinazolinedione rings such as above-described, may be used as starting materials in the manufacture of various polymeric substances and particularly of polyesters and polyamides.

For the manufacture of polyester resins which are the main object of this invention, the most suitable dicarboxylic compounds are those complying with general formulae (1) and (II) in which radicals R are aromatic radicals, radicals R are selected from the hydrogen atom and the akyl radicals having from l to 6 carbon atoms and radical R is an alkyl radical having from 1 to 6 carbon atoms.

The polyester 2,4quinazolinedione resins, according to the invention, are hereunder defined as being formed of a polycarboxylic component and of a polyhydroxyl component.

By these terms, there are meant the totality of the multivalent groups of the type A [-CO-],,, contained in the polyester, where the CO groups are ester carbonyles, A is the radical of the corresponding polycarboxylic acid, and the integer m indicates its functionality" (which may be for example, 2, 3 or 4), and the totality of the multivalent groups of the type B [O],, contained in the polyester, in which the divalent oxygen atoms derive from hydroxyl groups, B is the radical of the corresponding polyol and the integer n indicates its functionality (which may be for example 2, 3, 4 or more).

The polyester-2,4-quinazolinedione resin according to the invention, is characterized in that its polycarboxylic component is derivated, in a proportion of 10 to 100% (preferably from 20 to of the carboxylic acid equivalents, from at least one dicarboxylic acid containing one or two 2,4-quinazolinedione groups, and complying with one of the following formulae:

in which the radical R is defined as above, in a proporpreferred diols being ethyleneglycol and neopentyltion of O to 90% (preferably from 50 to 80%) of the glycol. carboxylic acid equivalents, from at least one polycar- The polyester-2,4-quinazolinedione resins according boxylic aromatic acid (for example di-, trior tetracar to this invention may be prepared according to any Y J; and in a proportion ofO to l% 0f the Car X- known direct esterification or transesterification techylic acid equivalents. from at least one aliphatic dicarnique, from convenient amounts of the polycarboxylic boxylic acid, which contains. for example, from 4 to reactants and of the suitable polyhydroxylated reaccarbon atoms; and in that its polyhydroxyl component tants. i5 derlvmed in 3 Proportion of 50 m 100% of the y- As a general rule, a plurality of polycarboxylic comdroxyl equivalents, from at least one polyol containing 10 pounds i l i at least three y y groups and, in a P 'P of in a proportion of l0 to [00%, (preferably from 20 O 50% Of the hydroxyl equivalents from at least to 50%) of the carboxylic functions involved, at least aliphatic or cycloaliphatic diol which contains, for exone of he dicarboxylic Compounds having ample from 2 w l carbon m quinazolinedione rings which comply with formulae (I) The preferred dicarboxylic acids of formulae (VIII) and n hereabove mfimionei and (IX) are those in which R is an aromatic radical, which may contain a single aromatic cycle, several joined aromatic cycles, or still several aromatic rings, separate or condensed, interconnected through a single bond, a divalent atom or a divalent group such as, for 20 example, O, S-, SO-, SO or -CH As examples of such dicarboxylic acids, there can be mentioned, as more particularly preferred, those in which R is a phenylene radical (for example 1,3- phenylene or l,4phenylene), tolylene, or a divalent in a proportion of O to 90% (preferably from to of the carboxylic functions involved, at least one of the above-defined polycarboxylic aromatic acids and/or one or more of their lower alkyl esters, and

in a proportion of O to 10% of the carboxylic functions involved, at least one of the above-defined aliphatic dicarboxylic acids and/or at least one of their lower alkyl esters, are caused to react with a plurality of polyhydroxylated compounds comprising:

radical derivated from diphenylmethane or diphenin aPmpomon of 50 to of the y f fuhc' ylether trons involved, at least one polyol containing at least AS examples of pglycarboxylic aromatic compounds three hydroxyl functions, selected for example, among there are to be mentioned: isophthalic acid, terephthe above'memlohed Ones and thalic acid, 4,4'-diphenylether dicarboxylic acid, tri- 3O n Proportion 0f 0 to the y y functions mesic acid and trimellitic acid, the preferred acid being Involved, at least One allphatlc cycloahphatic diOl.

r h h li id, selected for example among those mentioned above.

The aliphatic dicarboxylic acids include for example: in the foregoing, by lower alkyl" there is meant an maleic, adipic, azelaic and sebacic acids. alkyl radical having from 1 to 6 carbon atoms. in most The polyols containing at least three hydroxyl groups 35 386 he methyl ester is used. include for example aliphatic triols such as glycerol, Among the dicarboxylic compounds having 2,4- l,l,1-trimethylol ethane 0r l,l,l-trimethylol pro ane, quinazolinedione cycles, which can be used for the aliphatic tetrols such as pentaerythritol, aliphatic hexmanu a ture f th polyester resins according to the ols, such as sorbitol or mannitol, or still heterocyclic invention, specific compounds are especially interesttriols such as tris (hydroxyethyl) isocyanurate, or tris 4O ing, and this is particularly the case of the following (hydroxy-propyl) isocyanurate, the preferred polyol meihyl esters: being the tris (hydroxyethyl) isocyanurate which here- 2,4-bis-tolylene [(7-methoxycarbonyl 2,4- inafter will be shortnamed, T.H.E.l.C. quinazolinedione)-3-yl] of the formula t CH O C ,N GO (in As examples of aliphatic or cycloaliphatic diols, there 55 4,4'm thyl n biphenylene-bis y y may be mentioned: ethyleneglycol, 1,4-butanediol, 1,5- 2,4-quinazolinedione)3-y l Of the formula:

l c v v C NY O\ l/. CO2 CilzI l N CH O N* /l m O O pentanediol, neopentylglycol,l,fi-hexanediol, 4,4'-oxy biphenylene-bis [(7-methoxycarbonyl 2,4-

l,6-trimethylhexancdiol or l,4-cyclohexanediol. the quinazolinedione)3 yl} of the formula:

a H l l c 1 0 c N 0 a x) or still 3-( p.methoxycarbonyl-phenyl)7- methoxycarbonyl 2,4-quinazolinedione, of the formula H l o CHOC N 52 K/:\ 00 CH \f \f 2 3 It is essential, in order to obtain resins exhibiting satisfactory properties, that the polycarboxylic reactants, and the polyhydroxylated reactants be introduced in such proportions that the ratio of the sum of the hydroxyl functions to the sum of the carboxylic functions be higher than 1 and preferably from 1.1 to 2.

The direct esterifictaion or the transesterification reaction may be advantageously conducted in a single step at a temperature of 150 to 230C (preferably from 190 to 220C) and in the presence of an esterfication or transesterification catalyst, consisting preferably of a tetra alkyl titanate whose alkyl groups contain 1 to 6 carbon atoms.

It is preferred to proceed in solution in a solvent whose boiling point is higher than 190C, such as N- methylpyrrolidone, cresylic acid, m-cresol or a mixture of cresols; the amount of solvent used is generally low, a proportion of dry substances of 60 to 90% by weight being generally convenient. The reaction time depends on the nature of the reactants, their proportions, the selected catalyst and solvent, as well as the temperature; for example, when the reaction is conducted at a temperature from 190 to 220C, the heating is performed over a period of generally from 6 to hours. It is preferable, during the reaction time, to release the volatile compounds formed in the esterification or transesterification reaction (water or alcohols). They may be recovered, and from their measured amount it is possible to estimate the degree of advance of the reaction.

In the manufacture of polyester-2,4- quinazolinedione resins according to the invention, the dicarboxylic compounds with 2,4-quinazolinedione rings may be used as pure compounds, but it is also possible, in order to avoid their separation from the reaction medium where they have been synthetized, to proeeed by directly adding to the raw product resulting from their synthesis, the other reactants required for the manufacture of the polyester-2,4-quinazolinedione resins and to subject the resulting mixture to the abovementioned reaction conditions.

The polyester-2,4-quinazolinedione resins, according to the invention, may be used particularly for the manufacture of coatings, more specially varnishes for enamelling metal electric conductors.

According to the method used for their manufacture, the polyester quinazolinedione resins according to the invention may be obtained in the form of solutions in a solvent or in a mixture of solvents, such as those above-mentioned. I

These solutions may be used as base varnishes for the manufacture of coating compositions, and particularly of enamelling varnishes for metal electric conductors. These base varnishes may be diluted by addition of one of the above-mentioned solvents or of a mixture of several of such solvents. They can also be diluted with aliphatic or aromatic hydrocarbons or still with aromatic hydrocarbon cuts, having preferably a boiling point higher than C.

In order to improve the capability of use of these base varnishes, particularly as coatings for metal electric conductors, it is possible to add thereto various ingredients, which generally are allowed to react therewith, either at cold, or by heating carried out for example during a period of from 1 to 4 hours, at a temperature of 90 to C.

Thus, there can be added thereto an alkyl titanate, such as hereabove defined, for example in a proportion of 0.1 to 10% by weight of the dry substance of the varnish.

There can be also added thereto, for example in a proportion of l to 15% by weight, a polyisocyanate such as for example, a so-called blocked triisocya nate produced by trimerizing 2,4-diisocyanate tolylene and blocked" for example by means of phenol (such as the products known under the trade marks Mondur S, Desmodur CTS" and Mondur SH").

There can be also added, for example in a proportion of 0.1 to 1% by weight, a metallic drying agent, such as for example, a metal octoate or naphthenate.

It may be also advantageous to incorporate to the varnish, for example in a proportion of l to 15% by weight, a phenol-aldehyde resin, such for example as a phenol-formaldehyde, cresol-formaldehyde, or still a melamine-formaldehyde resin.

An addition of biphenyle, for example in a proportion of 0.5 to 2.5% by weight, may, in some cases, improve the surface state of the coatings obtained by means of the varnishes.

The above-indicated proportions are expressed as a weight of additive per weight of dry substance of the varnish.

In order to carry out the enamelling of the metal electric conductors by means of such varnishes, any usual technique can be used.

The following examples are given for mere illustrative purpose and must not to be considered as limitative of the scope of the invention.

Examples 1 to 11 illustrate the manufacture of 2,4- quinazolinedione dicarboxylic compounds.

Examples 12 to 20 illustrate the manufacture of polyester-2,4-quinazolinedione resins and their use for coating metal wires. In these examples the qualities of the enamelled wires may be estimated according to the following methods:

the flexibility of the wires is determined by subjecting them to a previous lenghthening and then by winding them around their own diameter (Mandrel test 1 X). The flexibility of the enamelling material expressed in is the maximum lengthening to which the enamelled wire may be subjected before succeeding in the winding test (i.e. without breaking of the enamelling layer).

The thermal resistance of the enamel is determined at 250C according to the standard A.I.E.E. No. 57. It is expressed in hours.

EXAMPLE 1 41.8 g of 2amino methyl terephthalate are dissolved in 150 ml of dioxane under an inert atmosphere, into a flask equipped with an ascending cooler and a mechanical stirrer. To this solution, there are added g of 4,4-diisocyanato-diphenyl methane and 66 mg of triethylamine acting as catalyst. The whole is brought to reflux, while maintaining the inert atmosphere and under stirring; a precipitate is formed during the first hours of heating which is continued for 47 hours.

After cooling, the precipitate is separated by filtration, thoroughly washed with ethyl ether and dried under vacuum at 100C up to a constant weight. There is obtained 48 g of a white product having a melting point higher than 330C, which has been identified by elementary analysis and infrared spectrum as being the 4,4'-methylene biphenylene-bis [(7-methoxycarbonyl 2,4-quinazolinedione) 3-yl}. Yield: 79.4

EXAMPLE 2 23.61 g of 4,4'-diisocyanato-diphenylmethane, 39.30 g of 2-amino methyl terephthalate and 100 mg of tri ethylenediamine, are intimately admixed, in the absence of air, in a flask provided with a small distillation column.

The mixture is heated for minutes to 200C and maintained at this temperature for 3 hours; during this time, there are recovered 5.1 g of methanol which distills from the flask. The residue is then crushed, washed with benzene, with ethanol and finally with ether.

By drying at constant weight, there are obtained 53. 1 g (yield 93.3 of a product whose infra-red spectrum is identical to that of example 1.

EXAMPLE 3 There is prepared, under dry nitrogen atmosphere, a solution of 17.3 g of methyl-amino terephthalate, 10g of 4,4'-diisocyanate-diphenylmethane and 250 mg of triethylenediamine in 60 ml of m-cresol. The solution is brought to the cresol reflux for 24 hours, and, after cooling, the formed precipitate is separated by filtration, washed with ethyl ether and brought to a constant weight by drying under vacuum at 100C. There are thus obtained 14.8 g (yield of 61%) ofa product having a melting point higher than 330C, which is identified by elementary analysis as being 4,4-methylene-biphenylene-bis- 7-methoxycarbonyl-2 ,4- quinazolinedione)-3-yl].

EXAMPLE 4 1n the same manner as described in Example 2, there are reacted 12.54 g of Z-amino methyl terephthalate and 13.14 g of bis-4,4'lN (carbophenoxy)amino] diphenyl-methane (4,4'-diisocyanato diphenylmethane blocked with phenol). The heating period under inert atmosphere is 47 hours, at a temperature of 200C.

After washing and drying, there are obtained 18g (yield of 98%) of 4,4'-methylene biphenylene bis [(7- methoxy carbonyl 2,4-quinazolinedione) 3-yl], as indi cated by the infra-red spectrum and the elementary analysis of the product.

EXAMPLE 5 A mixture of 41.8 g of 2-amino methylterephthalate having a melting point of 755C, 25.2 g of 4,4- diisocyanato diphenyl ether, 500 m1 of dioxane and 5 ml of triethylamine are heated to the dioxane reflux, while stirring during 24 hours, in the absence of moisture. A rapid formation of a precipitate occurs after 1 or 2 hours of heating. After cooling and filtration, the obtained white fine precipitate is thoroughly washed with ethyl ether and then dried by heating under vacuum at 80C.

There are thus obtained 42.1 g (yield of of a product which was identified by elementary analysis and 1.R. absorption spectrum as being the 4,4'- oxybiphenylene-bis [(7-methoxycarbonyl-2,4- quinazolinedione)-3-yl], which has a melting point higher than 330C.

EXAMPLE 6 7.56 g of 4,4-diisocyanato-diphenylether and 13.0 g of 2-amino methyl terephthalate are heated to ZOO-210C under dry nitrogen atmosphere. After heating for 30 hours, the mixture is allowed to come back to room temperature and the residual product is crushed, washed with ethyl ether and dried. There are obtained 17.5 g (yield of 94%) of a product having the same structure as that obtained according to example 5.

EXAMPLE 7 41.8 g of Z-amino methylterephthalate and 35.6g of 1,6-bis-[N-(carbophenoxy)amino]-hexane are placed in a flask scavenged with an inert gas. The intimate mixture of these products, finely crushed, is then brought to 150C for 7 hours, and thereafter to 200C for 15 hours. After cooling, washing with ethyl ether and drying, there are recovered 38.4 g (yield of 73.5 of Lohexamethylene-bis [(7-methoxycarbonyl 2,4-quinazolinedione) 3-yl], having a melting point of 290C.

EXAMPLE 8 An intimate mixture of 17.4 g of 2,4-diisocyanatotoluene, 44g of 2-aminomethyl terephthalate and 0.5 g of triethylene diamine are heated progressively to 150C under inert atmosphere. The mixture is maintained for 4 hours at 150C, then brought to 200C and maintained for 15 hours at this temperature. The mixture is then cooled, the residue is finely crushed, thoroughly washed with benzene, with ethanol and with ethyl ether, and then dried at constant weight under vacuum. There are thus obtained 45.77 g of 2,4- toluene bis [(7-methoxycarbonyl 2 ,4- quinazolinedione) 3-yl].

EXAMPLE 9 A solution of 19.1 g of 4-isocyanato-ethyl benzoate, 23.7 g of 2-amino ethyl terephthalate and 0.5 g of triethylamine in 150 m1 of dioxane, are brought to reflux while stirring under inert atmosphere. After 20 hours of reflux, the mixture is cooled, the precipitate is separated by filtration, washed with ethyl ether and dried. There are thus obtained 47.7 g (yield of of 3-(pethoxycarbonyl phenyl) 7-ethoxycarbonyl 2,4- quinazolinedione.

EXAMPLE 10 18.1 g of Z-amino terephthalic acid are dissolved in a solution prepared from 8 g of sodium hydroxide and 100 ml of water. This solution is placed in a vessel provided with a very efficient stirring system adapted to carry out interfacial reactions.

To the aqueous solution, vigorously stirred, is added a solution of 25 g of 4,4'-diisocyanatodiphenylmethane in 100 ml of benzene. At the end of this addition, the stirring is continued for 2 hours at room temperature; the formed precipitate is filtrated, treated in suspension by normal hydrochloric acid, then thoroughly washed with water. After drying, there are obtained 41 g (yield of 93%) of the expected tetraacid urea.

EXAMPLE 1 1 20 g of the product prepared according to example 10 are heated for 5 hours at 100C in 100 ml ofa mixture by equal volumes of acetic anhydride and pyridine. After cooling, there are separated 16 g (yield of 86%) of 4,4-methylene biphenylene bis- [(7-carboxy 2,4- quinazolinedione) 3-yl] having a melting point higher than 330C.

EXAMPLE 12 In a four neck glass reaction vessel, of a liters capacity, equipped with a mechanical stirrer, driven with a power engine, provided with a thermometer and a steam discharge tube, there are introduced 514.6 g of 4,4-methylene biphenylene-bis [(7-methoxycarbonyl- 2,4-quinazolinedione) 3-yl], 743.8 g of methyl terephthalate, 778.4 g of T.H.E.1.C. and 158.5 g of ethyl ene glycol, 292 g of m-cresol and 8.7 g of isopropyl titanate. The stirred mixture is brought to 200C in 40 minutes, then maintained for 9 hours at this temperature, while continuing the stirring. During this period, 91 g of distillate are recovered by condensation of the vapors evolved from the reaction medium. The temperature is allowed to decrease down to 170C, and the solution is diluted by adding thereto 2,333 g of m-cresol,' while vigorously stirring for homogeneizing the mixture. The temperature is then allowed to decrease to 120C and the solution is diluted by addition of 1313 g of Solvesso 100", and 87 g of Desmodur CTS together with 43.5 g of isopropyl titanate are added thereto. The mixture is stirred for 2 hours at 120C and allowed to cool down to room temperature. There is thus obtained a homogeneous solution of deep brown colour, having a viscosity at 30C of 610 cst.

This solution is used for enamelling a copper wire of 80/100 mm, fed at a feeding rate of l m/minute, to a vertical oven of a l meter length, at a maximum temperature of 400C. After 6 coatings, the wire is covered with an enamel layer of about 10/100 mm. This wire exhibits a homogeneous and smooth aspect.

Its flexibility is its average life time, at 250C, is 1,200 hours, which is a far higher performance than that of the products of class H (average life time, at this temperature, of 240 hours). The enamelled wire further shows an excellent directional abrasion, a good thermoplasticity (greater than 400C), and no loss when extracted with alcohol and toluene.

EXAMPLE 13 In a three-neck flask, equipped with a stirrer, a thermometer and a release tube, there are placed 34.25 g

of 4,4'-methylene biphenylene-bis [(7- methoxycarbonyl 2,4-quinazolinedione) 3-yl], 104.8 g of methyl terephthalate, 20 g of ethylene glycol, 1002 g of T.H.E.1.C., 32 g of m-cresol and 500 mg of butyltitanate. This mixture is heated to 200C, while stirring, for 8 hours, then to 220C for 1 hour and it is thereafter allowed to cool down. It is diluted by addition of 334 g of m-cresol and 91 g of Solvesso 100, these additions being made at a temperature of 120C. 2.5 g of butyl titanate and 14 g of Desmodur CTS are then added to the homogenized solution, and the mixture is maintained for 3 hours at 120C. After cooling, there is obtained a homogeneous varnish, whose viscosity at 30C is 950 cst.

This varnish has been used for enamelling a copper wire of /100 mm. The enameled wire has a flexibility of 25% and its life time, measured at 250C, is 420 hours.

EXAMPLE 14 In the same operating conditions as in example 13, there is heated a mixture consisting of:

43 g of the product obtained by condensation of 2 moles of methyl-amino terephthalate with 1 mole of 4,4'-diisocyanato-diphenyl methane, this condensation being conducted at reflux of the m-cresol for 6 hours.

46.6 g of methyl-terephthalate 52.2 g of T.H.E.l.C.

10.4 g of ethylene glycol 21.2 g of m-cresol 0.3 g of isopropyl titanate.

After heating for 10 hours at 200C, the mixture is diluted with 164 g of m-cresol and 92 g of Solvesso 6 g of Desmodur CTS are then added at a temperature of C, and the mixture is stirred for 2 hours 30 minutes at this temperature.

The resulting varnish solution has a viscosity of 1,100 cst at 30C. It was used for Coating a copper wire. The obtained enamel has a flexibility of 15%, its life time at 250C is longer than 1,300 hours, and its resistance to abrasion is exceptional.

EXAMPLE 15 There is heated at 210C, for 8 hours a mixture consisting of:

31.5 g of 4,4'-oxy-biphenylene-bis 7- methoxycarbonyl 2,4-quinazolinedione) 3-yl] 45.4 g of methyl terephthalate 44.9 g of T.H.E.1.C.

7 g of ethylene glycol 0.5 g of isopropyl titanate 20 g of m-cresol.

160 g of cresol, 80 g of Solvesso 100, 2 g of isopropyl titanate, 10 g of Desmodur CTS and 10 g of a phenolformaldehyde resin, are added tothis solution, and the resulting mixture is maintained for 2 hours at C. The resulting solution has a viscosity of 880 cst at 30C. When used for coating a cylindrical copper wire, it gives an enamelled wire exhibiting very good flexibility properties: 20 to 25% of lenghthening before mandrel 1 X. lts thermal stability at 250C is 1050 hours (higher than that of class H).

EXAMPLE 16 In a flask having three tubes, provided with a thermometer, a mechanical stirrer and a release tube for recovering the distillates, there are placed 12.5 g of 4,-

4'-diisocyanatodiphenylmethane, 20.9 g of methyl amino terephthalate, 0.3 g of tributylamine and 24 g of m cresol. This mixture is brought to the cresol reflux for 6 hours, under dry nitrogen atmospherev The mixture is allowed to cool down to 150C, and 38.8 g of methyl terephthalate, 40 g of T.H.E.1.C. and 44g of ethyleneglycol are added thereto. As catalyst, 0.2 g of butyl titanate are also added and the whole mixture is then heated, under vigorous stirring, to 210C, said temperature being maintained for 9 hours. The dilution of the varnish is conducted at 120C, by successively adding 125 g of m-cresol and 75 g of Solvesso 100, so as to obtain a solution containing about 30% of dry substance. l g of butyl titanate, 3 g of Desmodur CTS and l g of biphenyl are added to the resulting solution. After these additions, the mixture is maintained for 3 hours at 120C under stirring. After cooling, the obtained homogeneous brown solution shows a viscosity, measured at 30C, of 1250 est.

A metal wire, enamelled by means of this solution, shows a deep brown coating of uniform colour and smooth aspect. It may be lenghthened by 15 to 20% before being subjected with success to the test of winding around its own diameter. lts directional abrasion and its adherence index are very good. lts life time at 250C is longer than 1000 hours.

EXAMPLE l7 1n the same manner as in example 16, 41.8 g of methyl amino-terephthalate are condensed with 25.2 g of 4,4-diisocyanato'diphenylether, in 57 g of cresol and in the presence of 0.6 g of tributylamine. After 4 hours of heating to reflux, 97 g of methyl terephthalate, 102.3 g of T.H.E.1.C., 26.8 g of ethyleneglycol and 0.7 g of isopropyl titanate are added thereto. The heating is continued at reflux for 10 hours and the mixture is then allowed to cool down to 125C; it is then diluted by adding 250 g of cresol and 150 g of Solvesso 100; there are also added 1 g of isopropyl titanate, 12g of Desmodur C1 S, 15 g of phenol-fomraldehyde resin and 1 g of cadmium naphthenate. After maintenance for 2 hours at 120C, the mixture shows a homogeneous aspect. At 30C, its viscosity is 1485 est. It gives a flexible enamelled wire (lengthening: resistant to abrasion and to heat (life time at 250C longer than 1000 hours).

EXAMPLE 18 30.2 g of 4,4-methylene biphenylene-bis [(7- methoxycarbonyl 2,4-quinazolinedione) 3-y1], 49.8 g of terephthalic acid, 57.9 g of T.H.E.l.C. and 16.3 g of neopentyl-glycol, are condensed together by heating for 9 hours at 210220C, in the presence of 0.6 g of isopropyl titanate and 30 g of cresylic acid.

During the heating, 3g of methanol and 9.8 g of water are recovered and removed from the reaction medium in the form of vapors. After dilution of the obtained mixture by addition of 150 g of cresylic acid and g of Solvesso 100. 2.5 g of isopropyl titanate, 12.5 g of Desmodur CTS and 10 g of phenol-formaldehyde resin, are added thereto.

After heating for 3 hours at C, the obtained varnish solution has a viscosity of 1310 est at 30C. It can be used for obtaining enamelled wires having very good mechanical properties (flexible and resistant to abra sion) as well as good thermal properties (life time at 250C longer than 1000 hours).

EXAMPLE 19 76.4 g of 2,4-toly1ene bis [(7-methoxycarbonyl 2,4- quinazolinedione) 3-y1], 155.2 g of methyl terephthal ate, 37.2 g of ethylene glycol and 156.6 g ofT.1-1.E.l.C. are admixed with 80 g of cresol and 1.5 g of isopropyl titanate. The whole mixture is brought to 210C for 8 hours in the manner described in Example 13.

The varnish is diluted by addition of 250 g of S01- vesso 100 and 420 g of cresol, 3.3 g of isopropyl titanate, 15 g of Desmodur CTS, 1 g of manganese naphthenate and 15 g of phenol-formaldehyde resin are incorporated to the solution. After heating of this new mixture for 2 hours at C, there is obtained a homogeneous solution having a viscosity of 1730 est at 30C.

Copper wires, enamelled by means of this solution, are coated with an adherent enamelling, resistant to abrasion, exhibiting a good flexibility and a good resistance to heat.

EXAMPLE 20 13.6 g of 3-( p.methoxycarbonyl-phenyl )7- methoxycarbonyl 2,4-quinazolinedione, 19.4 g of methyl terephthalate, 20.9 g of T.H.E.l.C., 5 g of ethylene glycol and 0.1 g of butyl titanate are heated for 6 hours at 200C, while stirring with 12 g of cresol. The resulting concentrated solution is diluted by addition of 70 g of cresol and 40 g of Solvesso 100; 1 g of isopropyl titanate, 2.5 g of Desmodur CTS, 2 g of cresolformaldehyde resin are then added thereto, and the mixture is brought to C for 1 hour. The resulting homogeneous solution has a viscosity of 800 cst at 30C. Wires which have been enamelled by means of this solution are of good quality.

In the above examples, the product referred to under the trade name Solvesso 100 consists of a mixture of hydrocarbon solvents and the products referred to under the trade name Desmodur CTS is a trimer of 2,4- tolylene diisocyanate blocked with phenol.

What we claim is:

l. A compound of the formula:

N o o l co a n R u a l o N R CO2P.

in which R is alkylene of l-20 carbon atoms, phenylene, tolylene, ethylphenylene, chlorophenylene, biphenylene, naphthylene, or a divalent radical of the formula:

wherein X is O, S SO S; ,or 2.

0 0 GOG.

biphenylene, or naphthylene.

5. A compound as defined by claim 3 wherein R is (CH wherein n is 1-10, phenylene or naphthylene.

6. A compound as defined by claim 2, said compound being selected from the group consisting of 4,4- methylcne biphenylene-bis[ (7-carboxy 2.4- quinazolinedione) 3-yl], the dimethyl ester thereof and the diethyl ester thereof.

7. A compound as defined by claim 2, said compound being selected from the group consisting of 4,4- oxybiphenylene-bis[(7-carboxy 2,4-quinazolinedione) 3-yl], the dimethyl ester thereof and the diethyl ester thereof.

8. A compound as defined by claim 2, said compound being selected from the group consisting of 1,6 hexamethylene-bis[ 7-carboxy 2 ,4-quinazolinedione) 3-yl], the dimethyl ester thereof and the diethyl ester thereof.

9. A compound as defined by claim 2, said compound being selected from the group consisting of 2,4-toly1ene bis[(7-carboxy 2,4-quinazolinedione)3-yl], the dimethyl ester thereof and the diethyl ester thereof.

10. A compound as defined by claim 3, said compound being selected from the group consisting of 3-(p. methoxycarbonyl phenyl)7-methoxylcarbonyl 2.4- quinazolinedione and 3-(p. ethoxy-carbonyl-phenyl) 7-ethoxycarbonyl 2,4-quinazolinedione.

11. A compound as defined by claim 6, said compound being said dimethyl ester. 

1. A COMPOUND OF THE FORMULA: (2,4-DI(O=),(R1-OOC-)-1,2,3,4-TETRAHYDROIN WHICH R IS ALKYLENE OF 1-20 CARBON ATOMS, PHENYLENE, TOLYLENE, ETHYLPHENYLENE, CHLOROPHENYLENE, BIPHENYLENE, NAPHTHYLENE, OR A DIVALENT RADICAL OF THE FORMULA: -1,4-PHENYLENE-X-1,4-PHENYLENEQUINAZOLIN-3-YL)2-R OR
 2. A compound as defined by claim 1 wherein said compound is Formula (I).
 3. A compound as defined by claim 1 wherein said compound is a compound of Formula (II).
 4. A compound as defined by claim 2 wherein R is (CH2)n wherein n is an integer from 4 to 8, phenylene, tolylene, ethylphenylene, chlorophenylene,
 5. A compound as defined by claim 3 wherein R is (CH2)n wherein n is 1-10, phenylene or naphthylene.
 6. A compound as defined by claim 2, said compound being selected from the group consisting of 4,4''-methylene biphenylene-bis((7-carboxy 2,4-quinazolinedione) 3-yl), the dimethyl ester thereof and the diethyl ester thereof.
 7. A compound as defined by claim 2, said compound being selected from the group consisting of 4,4''-oxybiphenylene-bis((7-carboxy 2,4-quinazolinedione) 3-yl), the dimethyl ester thereof and the diethyl ester thereof.
 8. A compound as defined by claim 2, said compound being selected from the group consisting of 1,6-hexamethylene-bis((7-carboxy 2,4-quinazolinedione) 3-yl), the dimethyl ester thereof and the diethyl ester thereof.
 9. A compound as defined by claim 2, said compound being selected from the group consisting of 2,4-tolylene bis((7-carboxy 2,4-quinazolinedione)3-yl), the dimethyl ester thereof and the diethyl ester thereof.
 10. A compound as defined by claim 3, said compound being selected from the group consisting of 3-(p. methoxycarbonyl phenyl)7-methoxylcarbonyl 2,4-quinazolinedione and 3-(p. ethoxy-carbonyl-phenyl) 7-ethoxycarbonyl 2,4-quinazolinedione.
 11. A compound as defined by claim 6, said compound being said dimethyl ester. 